Computing devices are increasingly requiring advanced two-dimensional (2D) and three-dimensional (3D) graphics applications. For example, computing devices are increasingly offering games, character animations, graphical menu systems and other applications that require advanced graphics rendering. This advanced graphics rendering, especially with 3D graphics, involves a substantial amount of data processing. The quality of the advanced graphics rendering may be limited by the amount of processing resources, the capability of the available processing resources, the amount of available power and the like.
For example, applications requiring advanced graphics rendering at a high rendering rate, e.g., measured as frames per second, may place a significant strain on the available computing resources. The strain on the available computing resources may result in a reduced performance in other applications, low quality graphics rendering, or both due to the heavy load placed on the computing resources. In the context of mobile computing devices, such as personal digital assistants (PDAs), wireless communication devices, global positioning devices and the like, the computationally intensive data processing required for graphics rendering may consume a significant amount of the available power of the mobile computing device.
A multi-media processor may include a general-purpose central processing unit (CPU) coupled to a graphics processing unit (GPU). The GPU is dedicated to perform graphics rendering operations to display computerized graphics on a display. GPUs are built with a highly-parallel structure that provides more efficient processing than conventional, general-purpose CPUs for a range of complex graphic-related algorithms. When the graphic-related algorithms executing on the CPU requires graphics processing, the CPU tessellates the graphics and provides the tessellations to the GPU for rendering to the display. The highly parallel nature of the GPU allows the GPU to create complex, three-dimensional images on the display more quickly than drawing the images directly to the display with the CPU. GPUs may be used in a wide variety of applications, and are very common in graphic-intensive applications, such as video games applications, complex graphical user interface applications, computer-aided design programs for engineering or artistic applications, or any other type of software application that uses 2D or 3D graphics.
Modern GPU architectures may include a tessellation stage. The tessellation stage may be hardware within the GPU and may be configured to perform specific fixed functions. As one example, the tessellation stage of the GPU may tessellate Quad or Triangle domains into smaller triangles. The domain may be considered as a portion of the image, and may include four sides (quad domain) or three sides (triangle domain). Vertices are buffered in a vertex reuse buffer of limited size, and the connectivity information for triangles is outputted. Due to the limited size of the vertex reuse buffer, some vertices need to be recalculated as the connectivity information comes in. Some example approaches produce around 1 primitive per clock cycle. This is not necessarily the case for all implementations, however.